In the third of a six-part draft preview series, the Fantasy Tracker helps you tackle the wide receiver position. Next week: tight ends, defenses and kickers.

They are high-flying, acrobatic, sometimes dominating. When a team is in need of a game-saving miracle, they look to wide receivers to save the day. There are many receivers who also can be the hero of your fantasy team.

Rule changes, roster makeup and skill sets have swayed the NFL toward a more pass-heavy league, making WRs a more valuable fantasy

commodity. Some fantasy-league rosters require three starting WRs or a flex, ramping up an already high demand for pass-catchers.

In the old days, smart fantasy owners normally planned to take running backs with their first two picks. The race to grab WRs hasn’t reached those levels. You still need to address your backfield in the first 4-5 rounds. But WRs populate more high picks now than ever.

TOP TIER

Calvin Johnson made it look too easy last season. With a full season working with starting quarterback Matthew Stafford now under his belt, we don’t expect the man known as Megatron to slow down much, making him worthy of a first-round selection.

The superpowers of Larry Fitzgerald are as strong as any WR, but his task is made more difficult by underwhelming QB play. Let someone else spend a high pick on him.

Instead, we prefer Andre Johnson. He battled hamstring injuries last season (his recent hammy woes are not deemed serious), starting QB Matt Schaub missed a significant portion of the season, and early on the team was without primary rushing threat Adrian Foster. All that meant is was easier to defend against Johnson, during those times he was on the field. The Texans, when healthy, are a high-powered offense, and we expect to have a better run of injury luck this season. Johnson is a solid second-round pick.

SECOND TIER

We expect Julio Jones to start eating into Roddy White’s chances — not enough to warrant a fourth-round pick of Jones, but too much to warrant a third-round pick of White.

Greg Jennings was consistent when on the field last year, but we worry about the Packers wide variety of options — we would rather take Jordy Nelson a round or two later. Though Wes Welker has been a dynamic fantasy player since arriving in New England, we could see his numbers dipping this year, enough to dissuade us from a third-round pick.

Is Victor Cruz the next Marques Colston of Miles Austn — guys who went from obscurity to a fantasy goalmine overnight — or is he the next Antonio Bryant or Braylon Edwards — one-season wonders who haven’t duplicated their breakout years? We don’t like that much uncertainty in Rounds 3-4, so instead we would take Hakeem Nicks. Reports indicate Nicks (foot) will be back in time for the season, but even if he misses a game or two, we think he will provide more fantasy production over the course of the season.

We’re not afraid of Mike Wallace’s contract squabbles. We expect him to play, and be productive — enough to justify a third-round pick. We also are comfortable taking Brandon Marshall in the fourth. We’re excited about his change of scenery and being reunited with QB Jay Cutler.

A.J. Green was great as a rookie. But will a sophomore slump make he and second-year QB Andy Dalton duds, like the Green Lantern? We’ll take the risk in Round 3.

Steve Smith showed last year, he hasn’t slowed down. The Panthers’ passing game ebbed as the 2011 season wore on, but the running game took off. Expect defenses, at least early in the year, to stack to box to stop the four-headed backfield monster, which should leave Smith running free for some big fantasy outings.

Miles Austin or Dez Bryant in Rounds 4-5 work as well.

THIRD TIER

This group is why you can wait to grab that second or third WR. Among the targets we deem safe, or even strong, in Rounds 5-7 include Brandon Lloyd, who could be Randy Moss-lite in New England. Demaryius Thomas now has Peyton Manning throwing to him, as does Eric Decker (look for him in Round 8).

And we won’t lose sleep if we end up with Dwayne Bowe, Jeremy Maclin or even Vincent Jackson in this range.

We’re not quite as high on DeSean Jackson, Pierre Garcon or Stevie Johnson, but prefer them to Marques Colston or Percy Harvin.

FOURTH TIER

Here, you’re looking for potential, like that of Torrey Smith. Robert Meachum should benefit from a move to San Diego. Reggie Wayne is a nice grab in Round 10.

Santonio Holmes can complain all he wants, but we’re not picking him, nor will we target Michael Crabtree or Justin Blackmon.

THE REST

If Kenny Britt misses time (knee injury or possible DUI suspension), we like Nate Washington. We believe the 49ers can whip Randy Moss into shape. We’re not so confident about Terrell Owens in Seattle — who we only would take with our next to last pick, right before a kicker.